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Lens review

Sigma 10-20 mm f/3.5 EX DC HSM

25 September 2009
Szymon Starczewski

4. Image resolution

The image resolution of Sigma 10-20 mm has been measured on the strength of RAW files from Nikon D200. We recently used the same camera body to test Tamron 10-24 mm and Nikkor 10-24 mm, so we’ll be able to make a direct comparison of the obtained results. In the case of Sigma, the measuring errors oscillated between 0.3 and 1.1 lpmm.

Sigma 10-20 mm f/3.5 EX DC HSM - Image resolution

The above graph shows the behavior of the tested Sigma at the center of the frame. Two things are blatantly visible here: very high MTF values and even behavior for all focal lengths. Both these characteristics make Sigma 10-20 mm win a duel against most of the competitors. Such high values weren’t there for Nikkor 10-24, or Tamron 10-24. Tokina 11-16 mm f/2.8 can take up a fight against Sigma, as after stopping down to f/3.5 (Sigma’s brightness) and taking into account the fact, that it was tested on a less dense with pixels Canon 20D’s sensor (the difference in MTFs of about 10%) it gives comparable results.

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How do the edges of the frame look? That’s an important question, as they were the biggest flaw of the older 10-20 mm model of worse speed. The case is explained on the graph below.

Sigma 10-20 mm f/3.5 EX DC HSM - Image resolution

Again, we have a very even behavior at all focal lengths and again MTF values that we can’t complain about. We’d want results of over 30 lpmm at the maximum aperture, but that’s about the only shortcoming we can notice. After stopping down to f/4.0, no matter what focal length is used, the image will be of at least good quality.

To sum up, we present clippings of our test chart.


Sigma 10-20 mm f/3.5 EX DC HSM - Image resolution